In recent years, many researches and developments have been conducted to improve the transfer rate in the mobile communication system. An example of a way to improve the transfer rate in the mobile communication system may include a way to use broadband signals. In order to transmit the broadband signals, there is a need to use, for example, quasi-millimeter waves which are higher in frequency than the microwaves which have been used till now. However, the use of the high carrier frequency signals may cause an increase in propagation loss, leading to, for example, the reduction in service area (or coverage) in which mobile communication service is available, or the significant deterioration of transmission quality.
Therefore, for example, the antenna array technology that ensures the quality of the communication lines by an array gain has attracted attention as propagation loss compensation technology. In addition, technology has been developed to detect a signal transmitted by a transmitting-side communication device, from a received signal which is received via a plurality of antennas. The signal detection technology may include, for example, technology disclosed in the following Non-Patent Document 1, or technology disclosed in the following Non-Patent Document 2.